I wonder how RWS 34 would shoot with Light pellets and a light plastic tophat.
It seems to me if you have a light tophat light pellets would get more fps maybe.
I remember a post of someone who chopped his barrel I think four inches, he was met with a harsh firing cycle, I would guess because less friction allowed the piston to build up peak pressure too quickly, as I recall he then tryed heavy pellets and a much smoother firing cycle resulted and his heavy pellets were going almost as fast as the light ones.
So here is the point, it you choose to chop your barrel use heavy pellets, heavy tophat you may get more FPE.
So here is the other point, if you use light pellets in .177 it may not hurt to try a lignt tophat with light pellets.


I would love to try chopping a RWS 34 in .177 with kodiaks.

Stuart Brandt

Stuart, I think you are missing some of the dynamics of the firing cycle. In your scenario, it seems the pellet moves when the piston moves. This isn't really the case. In the example of the guy that did a barrel chop, most likely the harsh firing came from the removal of the barrel choke, not the short length. Many experiments have shown that shortening the barrel of a spring gun has virtually no effect on velocity till the barrel is less than ten inches. Taking away the choke allows the piston to strike the front end of the compression chamber without benefit of a cushion of air to help it decelerate. A heavy pellet will surely help, but then it becomes a balancing act with the pellet weight. I believe that is why an unchoked barrel shoots fewer pellets well. Dianas are pinch choked, so the choke isn't even round! A good choke can be applied with a modified tubing cutter to produce a consistent, round constriction.